Merge changes from topic "kleaf_bazel_800" into main

* changes:
  Update for using Bazel 8.0.0.
  Mock rules_shell.
tree: 6c4943623dead7fa04ddfe76d059876849d1ae7c
  1. gbl/
  2. libxbc/
  3. vts/
  4. .clang-format
  5. .gitignore
  6. BUILD
  7. LICENSE
  8. OWNERS